Improved screw-wrench



UNITED STATES PATENT OEEICE.

GEORGE B. READ, OF NEW YORK, N. Y.

IMPROVED SCREW-WRENCH.

Specification forming part of Letters Patent No. 9,567, dated February1, 1S53.

invented a new and Improved lVrench; and.

I do hereby declare that the following is a full, clear, and exactdescription of the same,

. reference being had to the annexed drawings,

making a part of this specification, in which- Figure l is a side viewof the wrench. Fig. 2 is also a side View of the same with thestationary jaw bisected, in order to show the pawl which catches intothe rack on the shank of the movable jaw. Fig. 3 is a section showingthe rack released from the pawl, in order that the movable jaw may beproperly adjusted, so that a bolt-head, nut.1 or other article designedto be turned by the wrench may be secured or iitted snugly between thetwo jaws.

Similar letters and figures of reference indicate corresponding parts incach of the several figures.

The nature of my invention consists in having the shank of t-headjustable jaw pass through a recessin the stationary j aw, which isattached by a pivot to the end of the wrenchstock. The shank of theadjustable jaw is provided with a rack, into which a pawl, attached tothe end of the wrench-stock, catches. By this arrangement, as will behereinafter shown, the two jaws as the handle of the wrench is turnedtend to bind or press rmly upon the nut, particularly upon the outercorners of it, and thus the jaws are prevented from slipping around thecorners of the nut.

The adjustable jaw is brought against the nut -by freeing the pawl fromthe rack, which is done by merely pressing the outer corner of thestationary jaw and the handle and stock of the wrench toward each other,as will be hereinafter shown. By thus freeing the pawl from the rack theshank of the adjustable jaw maybe moved within the recess in thestationary jaw.

To enable others skilled in the art to make and use my invention, I willproceed to describe its construction and the manner in which it is used,or operated.

A represents the stock of the wrench, to which stock is affixed thehandle B.

C is a jaw attached by a pivot a to the end of the stock A. The jaw Chas a square recess through it, through which recess the shank D of thejaw F. passes or works. On one of the sides of the shank D there is arack b, into which a pawl F, attached to the end of the stock A,catches. (See Fig. 2.) A spring g bears against the pawl F and keeps itin the rack. the stock A. j

By referring to Fig. 2 the operation and object of the arrangement willbe readily understood.

It will be seen that by drawing or turning the handle B in the directionindicated by the arrow 2 the two jaws E C will be forced toward eachother, because the stock A is a lever having its fulcrum at a, and thepawl F is attached to the end of the stock to a projection c.Consequently when the handle-is moved or turned in the direction of thearrow 2 the pawl F will force or press the shank D and jaw E in thedirection of the arrow 3, and the jaw C will move in the direction ofarrow 4. Therefore the nut d (see dotted lines) has the two jaws E Opressing irmly upon two of its sides as the handle and stock of thewrench are moved or turned. The pressure ofthe jaws will be the greatestat the outer corners 5 6 of the nut G, because the pivot or fulcrum a isat the corner of the jaw C, and the line of pressure will be in thedirection indicated by the dotted line d. Thus the jaws arepreventedfrom slipping around the corners of the nut as the wrench is turned.

The jaws are adjusted to the nut in the following simple manner: Thecorner e of the jaw C and the end f of the stock A are pressed towardeach other in the direction indicated by arrows l l. (See Figs. 2 and3.) By doing this the pawl F is thrown from the rack b, as seen in Fig.3, in consequence of the projection 7L acting against'it, andconsequentlythe shank D may be moved in the recess and the jaw E movednearer to or farther from the jaw O, so that nuts of different sizes maybe operated upon and grasped firmly by the jaws.

The jaw E,I term the adjustable jaw, as it is moved,when being adjustedto a nut, independently of the jaw C, and the jaw C, I term a stationaryjaw, as it has no motion communicated to it except that given it byturning or moving the handle of the wrench.

I do not claim having the jaw E attached to a shank and the shankpassing through a recess in the jaw C independent of the mode One end ofthat spring is attached to of operating the jaws, for the above device,differently modified, is employed in various Wrenches now in use; but

Vhat I claim as new, and desire to secure by Lett-ers Patent, is-

The arrangement of the several parts, as herein shown anddeseribed--viz., the jaw C, being attached by a pivot a to the stock A,and said jaw C having a recess through it, through which recess theshank D of the adjustable jaw E passes, the shank D being provided witha rack l), into which a paWl F, at-

tached to the end of the stock, catches, said pawl being kept into therack b by the spring g, by which arrangement the two jaws E C are forcedagainst the sides of the nut as the handle of the wrench is turned andthe jaws made to bear or bind harder upon or near the corners 5 and 6 ofthe nut, thus preventing the jaws from slipping around it.

G. B. READ. Witnesses:

A. D. MUNN, S. H. WALES.

